1. Field of the Invention
The present invention relates to an apparatus and method for separating brine shrimp eggs (artemia cysts) from a slurry containing an agglomeration of adult brine shrimp (artemia), artemia cysts, and debris. More particularly, the present invention relates to introducing the slurry into a rotating drum having openings to allow the cysts to pass through, providing a liquid source to maintain the slurry, and disposing a spray nozzle to spray against the outside surface of the drum to clean the adult brine shrimp and debris from the openings.
2. Prior Art
Brine shrimp of the genus Artemia, and specifically of the species Atremia salina, are primitive crustaceans which normally inhabit bodies of water having a high saline content, such as the Great Salt Lake in Utah. Brine shrimp serve as a source of food for many fish. Brine shrimp have been harvested for many years and are used as fish food on a commercial basis. Brine shrimp eggs are contained within protective spherical cysts or shells of hemoglobin. Brine shrimp eggs are remarkable in that they can be dried and stored and then hatched years later by returning them to salt water. The eggs may be nurtured to shrimp which are used as food in shrimp farms and the like producing food for human consumption. The ability to stockpile dried brine shrimp eggs for future hatching has made commercial harvesting of the eggs a profitable venture.
Brine shrimp and their eggs agglomerate in floating colonies at the surface of the water. Typically, the eggs occupy the top one quarter inch of water. The eggs are extremely small; approximately seven million brine shrimp eggs are contained in a single ounce. Adult brine shrimp are a thousand times larger than the egg.
The eggs are harvested by collecting the eggs left along the beaches or by off-shore harvesters. Due to the small size of the eggs, they are very difficult to harvest. In addition, because of the nature of the adult brine shrimp to agglomerate, the eggs are harvested along with adult brine shrimp and other debris.
Attempts have been made to screen the slurry of shrimp, eggs and debris in order to separate the eggs from the debris and adult brine shrimp. This is difficult because the adult brine shrimp agglomerate, trapping the eggs. In addition, the debris and adult shrimp tend to clog the openings in the screen, preventing eggs from passing through the screen.
Typical prior art devices and methods for screening the eggs comprise a horizontal screen which is vibrated. The brine shrimp and the debris clog the openings of the screen requiring the process to be stopped in order to clean the screens. Thus, these devices and methods require that the separation process be done in batches which is slow and inefficient. A more continuous device and method which configures the screen as a conveyor belt has been attempted with limited success.
Therefore it would be advantageous to develop an apparatus and method for separating brine shrimp eggs from a slurry containing an agglomeration of adult brine shrimp, eggs and other debris.